1. Technical Field of the Invention
The present invention relates generally to a power saving system for a recording/reproducing apparatus designed to record or reproduce information on or from optical discs such as MDs (Mini Discs), MD2s, video CDs (Compact Discs), high-quality CDs, CD-Rs, CD-RWs, DVDs (Digital Versatile Discs), DVD-ROMs, DVD-Rs, DVD-RAMs, DVD-RWs, DVD+RWs, and MO (Magneto-Optical) discs, and more particularly to a power saving system for an optical disc recording/reproducing apparatus having a temporary memory for storing the data for data compression or decompression or shock-proofing.
2. Background Art
Recently, various types of portable recording/reproducing apparatus using an optical disc such as a CD, a DVD, or a MD appear on the market.
Usually, such portable recording/reproducing apparatuses have a shock-proof memory. For instance, MD portable players have a shock-proof memory of a capacity of about 4 Mbit and, in the playback mode of operation, holds the information content equivalent to a playback time of about 10 sec. in the memory temporarily, while kicking a pickup cyclically between adjacent track turns until one of sectors on which information is to be recorded next. In a record mode, after audio signals are compressed and stored in the shock-proof memory, they are read out of the memory and recorded on a MD for a preselected period of time. A sequence of these operations is carried out cyclically to record all audio signals on the MD. During a time interval between cyclic recordings of the audio signals on the MD, the pickup is kept kicked to track one of track turns for waiting one of sectors on which audio signals are to be recorded next.
Such portable players are required to record or reproduce data for an increased period of time. To this end, it is necessary to prolong the service lift of a battery, or to save as much of power consumed in the player as possible.
It is therefore a principal object of the present invention to avoid the disadvantages of the prior art.
It is another object of the present invention to provide a recording/reproducing apparatus having a power saving system for prolonging the record or playback time.
According to one aspect of the invention, there is provided an optical recording apparatus. The optical recording apparatus comprises: (a) a temporal memory which stores therein a signal to be recorded on an optical disc which is compressed at a given compression rate; (b) a data storage monitoring circuit which monitors the amount of the compressed signal stored in the temporal memory and provides a signal indicative thereof; (c) a pickup which emits light onto the optical disc to record the compressed signal read out of the temporal memory and receives a return of the light from the optical disc to output a signal; (d) a first servo circuit which produces servo error signals based on the signal outputted from the pickup; (e) a second servo circuit which is responsive to the servo error signals from the first servo circuit to subject the pickup to focus, tracking, and traverse control; and (f) a power saving circuit which is responsive to the signal from the data storage monitoring circuit to save power supplied to a preselected circuit component of at least one of the first and second servo circuit during a time interval in which the amount of the compressed signal stored in the temporal increases from a first level to a second level.
In the preferred mode of the invention, a compression rate determining circuit is further provided which determines the compression rate of the signal to be recorded on the optical disc. The power saving circuit determines the second level based on the compression rate.
The power saving circuit resumes the supply of power to the preselected circuit component after the amount of the compressed signal stored in the temporal reaches the second level.
A signal type specifying circuit may be provided which specifies a type of the signal to be recorded on the optical disc. The power saving circuit performs a power saving operation based on the type of the signal specified by the signal type specifying circuit and determines a timing with which the supply of power to the preselected circuit component is resumed based on the type of the signal.
A disc type specifying circuit may be provided which specifies a type of the optical disc. The power saving circuit performs the power saving operation based on the type of the signal specified by the signal type specifying circuit and the type of the optical disc specified by the disc type specifying circuit and determines the timing with which the supply of power to the preselected circuit component is resumed based on the type of the signal and the type of the optical disc.
A linear velocity determining circuit may also be provided which determines a linear velocity of the optical disc based on the type of the signal. The power saving circuit performs the power saving operation and determines the timing with which the supply of power to the preselected circuit component is resumed based on the type of the signal and the linear velocity of the optical disc.
According to the second aspect of the invention, there is provided an optical reproducing apparatus. The optical reproducing apparatus comprises: (a) an error correcting circuit which subjects data reproduced from an optical disc to error correction; (b) a temporal memory which stores the data corrected in error by the error correcting circuit in a data storage stage; (c) a data storage monitoring circuit which monitors the amount of the data stored in the temporal memory and provides a signal indicative thereof; (d) a reproducing circuit which reads the data out of the temporal memory in a data readout stage following the data storage stage and outputs the data for reproduction; and (e) a power saving circuit which is responsive to the signal from the data storage monitoring circuit to save power supplied to at least the error correcting circuit during a time interval in which the amount of the data stored in the temporal decreases from a first level to a second level in the data readout stage.
In the preferred mode of the invention, the apparatus further comprises a pickup which optically picks up the data from the optical disc, a driver which drives the pickup under servo control, a playback/servo circuit which produces a data signal and a servo error signal from the data picked up by the pickup, provides the servo error signal to the driver for use in the servo control of the pickup, and holds the data signal in the temporal memory, and a tracking circuit which subjects the pickup to tracking control. The reproducing circuit reads the data signal out of the temporal memory and decompresses the data signal. The power saving circuit saves the power supplied to at least the error correcting circuit and the tracking circuit during the time interval in which the amount of the data stored in the temporal decreases from the first level to the second level in the data readout stage.
According to the third aspect of the invention, there is provided an optical reproducing apparatus. The optical reproducing apparatus comprises: (a) a first control circuit which controls rotation of an optical disc in a first servo control mode based on a speed control signal derived from a drive circuit rotating the optical disc; (b) a second control circuit which controls rotation of the optical disc in a second servo control mode based on a speed control signal derived from data reproduced from the optical disc; (c) a driver circuit which drives a pickup reading the data out of the optical disc; (d) a playback/servo circuit which produces a data signal for playback and a servo error signal from on the data picked up by the pickup; (e) a focus control circuit which subjects the pickup to focus control; (f) a tracking control circuit which subjects the pickup to tracking control; (g) an error correcting circuit which subjects the data read out by the pickup to error correction; (h) a temporal memory which stores the data corrected in error by the error correcting circuit in a data storage stage; (i) a data storage monitoring circuit which monitors the amount of the data stored in the temporal memory and provides a signal indicative thereof; (j) a reproducing circuit which reads the data out of the temporal memory in a data readout stage following the data storage stage and outputs the data for reproduction; and (k) a controlling circuit which is responsive to the signal from the data storage monitoring circuit to save power supplied to at least the error correcting circuit during a time interval in which the amount of the data stored in the temporal decreases from a first level to a second level in the data readout stage. The controlling circuit switches control of the rotation of the optical disc from the second servo control mode to the first servo control mode.
According to the fourth aspect of the invention, there is provided an optical reproducing apparatus. The optical reproducing apparatus comprises: (a) a driver circuit which drives a pickup reading data out of the optical disc; (b) a playback/servo circuit which produces a data signal for playback and a servo error signal from on the data picked up by the pickup; (c) a servo circuit which provides a servo signal to the driver circuit based on the servo error signal from the playback/servo circuit; (d) an error correcting circuit which subjects the data read out by the pickup to error correction; (e) a temporal memory which stores the data corrected in error by the error correcting circuit in a data storage stage; (f) a data storage monitoring circuit which monitors the amount of the data stored in the temporal memory and provides a signal indicative thereof; (g) a reproducing circuit which reads the data out of the temporal memory in a data readout stage following the data storage stage and outputs the data for reproduction; and (h) a power saving circuit which is responsive to the signal from the data storage monitoring circuit to save power supplied to at least one of the drive circuit, the playback/servo circuit, and the error correcting circuit during a time interval in which the amount of the data stored in the temporal decreases from a first level to a second level in the data readout stage.
In the preferred mode of the invention, a transfer rate detector is further provided which detects a transfer rate of the data picked up from the optical disc. The power saving circuit performs a power saving operation based on the transfer rate of the data detected by the transfer rate detector and determines a timing with which supply of power is resumed based on the transfer rate.
A signal type specifying circuit may be provided which specifies a type of the data signal reproduced from the optical disc. The power saving circuit performs a power saving operation based on the type of the data signal specified by the signal type specifying circuit and determines a timing with which the supply of power is resumed based on the type of the signal.
A disc type specifying circuit may be provided which specifies a type of the optical disc. The power saving circuit performs a power saving operation based on the type of the optical disc specified by the disc type specifying circuit and determines a timing with which supply of the power is resumed based on the type of the optical disc.
A linear velocity determining circuit may also be provided which determines a linear velocity of the optical disc based on the type of the signal. The power saving circuit performs the power saving operation and determines the timing with which the supply of power is resumed based on the type of the signal and the linear velocity of the optical disc.
According to the fifth aspect of the invention, there is provided an optical reproducing apparatus. The optical reproducing apparatus comprises: (a) a pickup reading data out of an optical disc optically; (b) a signal producing circuit producing a reproduction signal containing control data and a servo circuit from the data read out by the pickup; (c) a servo circuit responsive to the servo signal to control readout of the data through the pickup; (d) a temporal memory storing therein the reproduction signal containing the control data; (e) a reproducing circuit reproducing the reproduction signal based on the control data; and (f) a power saving circuit saving a portion of power consumed in the apparatus during a reproduce mode of operation of the reproducing circuit.
According to the sixth aspect of the invention, there is provided an optical reproducing apparatus. The optical reproducing apparatus comprises: (a) a pickup reading data out of an optical disc optically; (b) a signal producing circuit producing a reproduction signal containing control data and a servo circuit from the data read out by the pickup; (c) a servo circuit responsive to the servo signal to control readout of the data through the pickup; (d) a temporal memory storing therein the reproduction signal containing the control data; (e) a reproducing circuit reproducing the reproduction signal based on the control data; (f) a first control circuit which controls rotation of an optical disc in a first servo control mode based on a speed control signal derived from a motor rotating the optical disc; (g) a second control circuit which controls rotation of the optical disc in a second servo control mode based on a speed control signal derived from the data reproduced from the optical disc; and (h) a power saving circuit saving a portion of power consumed in the apparatus during a reproduce mode of operation of the reproducing circuit, the power saving circuit switching control of the rotation of the optical disc from the second servo control mode to the first servo control mode.
In the preferred mode of the invention, the power saving circuit selects one of a plurality of power save operation modes based on a controlled content of the control data.
The power saving circuit may determine a power save duration based on a controlled content of the control data.